1. Field of the Invention
The present invention generally relates to a connecting block and conduit connection for vehicle air-conditioning systems. More specifically, this invention relates to a connecting block conduit connection, wherein an alignment element assures an efficient and reliable connection between a conduit connected to a housing of an air-conditioning component for a vehicle, in order to squarely align a relatively short conduit end within a conduit port of the housing.
2. Description of the Prior Art
Prior to the present invention, many types of sealing configurations have been proposed for connecting a conduit or tube to another component of a fluid system. Perhaps most common is the use of a simple O-ring encircling an end of a tube that is mounted into a port of a housing. The tube is connected to the port using a coaxial fastener that encircles and entraps the tube. The coaxial fastener is then screwed down over corresponding threads on the port—similar to a compression fitting—as is known in the art. Although this configuration is very simple and robust against leakage, its primary drawback is that it cannot be assembled quickly enough without damage to the O-ring for the modern-day assembly line. In order to torque the fastener to the port it is necessary to use hand tools, which is too time consuming. Therefore, devices such as block conduit connections were developed since they are easily assembled and quickly torqued down using a power tool.
The block conduit connection involves a connecting block typically having a teardrop-shaped profile. The connecting block entraps the conduit through a conduit passage therein. In addition, the connecting block houses a fastener through another passage just offset from and aligned parallel to the conduit passage. A simple bolt-style fastener is used to draw the connecting block and conduit into the port, such that the connection can be made quickly by torquing down the fastener with a power tool.
The block conduit connection, however, tends to be more susceptible to leakage than coaxial fastener connections and can present significant warranty problems to automobile manufacturers if not assembled properly. Leakage can occur in conditions where the connecting block and conduit are not properly aligned to the housing. In other words the mounting surfaces of the connecting block and housing are not parallel or flush, and the conduit is not squarely aligned within the port. Additionally, the fastener imparts a maximum hold down force along the axis of the fastener, but doesn't completely hold down the block at the end of the block opposite the fastener, and therefore cannot correct the misalignment condition. The misalignment condition normally leads to a pinched O-ring condition in which leakage is also likely to occur. Therefore, under high pressure conditions, fluid can leak out of the end of the block conduit connection at the end opposite the fastener, due to a pinched O-ring and/or misalignment and a lack of sufficient hold down force.
An example of such a defective block conduit connection 10P is illustrated in FIG. 1. For example, a conduit 50P and connecting block 30P are shown misaligned cross-axially relative to a conduit port 24P in a housing 20P. This misalignment is often due to incorrect assembly of the block conduit connection 10P. In other words, the longitudinal axis of a fastener 70P is not coaxially aligned with the conduit 50P. Torquing the fastener 70P results in a maximum hold-down force along the axis of the fastener 70P and a reduced hold-down force at the opposite end of the connecting block 30P at the far edge of the conduit 50P. Therefore, the connecting block 30P does not mount flush against the housing 20P and likewise, the conduit 50P does not mount squarely within, or misaligns cross-axially with respect to, the conduit port 24P. Cross-axial misalignment results in assembly defects such as cutting, pinching, or insufficient “squeeze” of an O-ring 58P as well as improper sealing of the O-ring 58P, thus permitting fluid to leak by. Therefore, it is important to ensure a square fit of the conduit 50P in the conduit port 24P and between the connecting block 30P and housing 20P. To be squarely aligned, the conduit 50P must be substantially at a right angle with respect to the mounting surface of the housing 20P.
To ensure a square fit between the connecting block 30P and the housing 20P, other block conduit connections 110P of the prior art provide for an extension pilot 56P on the end of the conduit 50P that pilots within a relatively long conduit port 24P, as shown in FIG. 2. The extension pilot 56P ensures straight and square alignment of the conduit 50P within the conduit port 24P of the housing 20P. Additionally, the tolerance stack up between the outer diameter of the extension pilot 56P and the inner diameter of the conduit port 24P is relatively tight to prevent misalignment therebetween. Accordingly, the result is a relatively long engagement length between the conduit 50P and conduit port 24P that enables square alignment therebetween. Unfortunately, the unnecessarily long engagement length and tight tolerances of these components is prohibitively expensive, uses extra material and weight, and consumes a large amount of space.
Therefore, what is needed is a device for a block conduit connection that requires a minimum of engagement length between the conduit end and the housing and ensures square alignment between the connecting block and conduit and the housing to reduce the potential for refrigerant leaks and therefore expensive damage to automotive air-conditioning equipment.